The present invention relates to a method for the purification of a polluted liquid, especially a washing liquid used at a washing installation.
Up to now it is common practice that in washing installations, such as car washes, the used washing liquid is collected in a collecting reservoir, and next, after the removal of oil and/or grease, is discharged at a sewer, whereas the washing installation is operated with clean water supplied by the public mains system. It is a disadvantage of this known method that the operating costs of the washing installation are high, because of the large need for fresh water. Further the environment is heavily polluted, while the costs originating therefrom are increasingly charged to the polluter, i.e. the owner or user of the washing installation. Further, water of the mains system is "unnecessarily" pure and thus relatively expensive for non-consumptive applications.